There are a wide range of applications in which it is desirable to select nucleic acids, such as DNA or RNA by size. For example, size selection is used in the production of DNA libraries for use in sequencing and other applications.
Various techniques for DNA size selection exist. Some of these techniques are undesirably labour intensive. One method for DNA size selection is to perform electrophoresis of a sample containing DNA in a gel. Since DNA of different sizes have different mobilities in the gel the electrophoresis separates the DNA into different bands by size. A band containing DNA in the desired size range can be identified and then manually cut out from the gel. The desired DNA can then be extracted from the gel.
Some electrophoresis systems comprise wells formed in a gel. DNA can be run into the wells by electrophoresis. Invitrogen E-gels and the Lonza Flash Gel™ provide such wells.
Y-channel size selection machines are another technology for DNA size selection. Examples are the Sage Pippin Prep™ and the Caliper XT™ machines. These machines can extract DNA of a desired size range from a sample by diverting DNA of the desired size range into a side channel and collecting the diverted DNA against a molecular weight cut-off filter.
Solid Phase Reversible Immobilization Beads (SPRI) beads which are available from Beckman Coulter and others may be used to trap DNA of a certain size and then release the DNA after a wash and a change in pH.
There remains a need for a DNA size-selection technology that can provide high throughput. There remains a need for a DNA size-selection technology that can provide accurate DNA size selection with reduced labour.